Data storage, satellite communications, wireless communications, wire-line communications, and power-line communications are applications that may each use codes such as LDPC codes to encode and decode data. Devices such as digital camera flash memory storage, satellites, mobile phones, and other mobile devices may also each use LDPC codes and LDPC decoders.
Error correction codes are used to fix errors in information transmitted in a noisy data storage or communications channel. The information may be encoded (by a LDPC encoder) prior to transmission and then subsequently decoded (by a LDPC decoder) when received. LDPC codes are one of the best performing error correction codes, along with Turbo codes, for use in correcting errors in information transmitted on communication and data storage channels.
Conventional hard decoding LDPC techniques typically determine whether to flip a bit or update the value of a symbol based only on whether a given number of checks are unsatisfied. For example, values of one or more symbols may be selected to be updated based on which combination of updated symbols is most likely to reduce the number of unsatisfied check nodes.